Select objects in scene by their object color
Based on your comment, I guess you want to compare against the viewport display color property:



I think one easy way to compare color values is appending the components to a new list and compare the resulting lists using the == operator.

&gt;&gt;&gt; [c for c in C.object.color]
&gt;&gt;&gt; [1.0, 1.0, 1.0, 1.0]
&gt;&gt;&gt;
&gt;&gt;&gt; [c for c in C.object.color] == [1.0, 1.0, 1.0, 1.0]
&gt;&gt;&gt; True


If you don't like lists for any reason, you can also convert the color to a tuple using the slice operator [:], which is even shorter -> thanks to @batFINGER:

&gt;&gt;&gt; C.object.color[:] == (1.0, 1.0, 1.0, 1.0)
True


Full script iterating through Scene.objects, comparing the color values (r,g,b,a) of each object against the values of Context.object and selecting the matches:

import bpy

ctx = bpy.context
obj = ctx.object

# Object color as list
obj_clr = [c for c in obj.color]

for o in ctx.scene.objects:
    if o != obj and o.type not in ('LIGHT', 'CAMERA', 'EMPTY'):
        # Compare both lists
        if [c for c in o.color] == obj_clr:
            o.select_set(True)

obj.select_set(False)


Be aware that there are might be issues with floating point precision when comparing the values. One way around that is using isclose(a, b, *, rel_tol=1e-09, abs_tol=0.0) provided by the math module, which can be wrapped into a little helper function to test all 4 floats at once:

def compare_color(a, b, t=0.001):
    from math import isclose
    comp = {isclose(i, j, abs_tol=t) for i, j in zip(list(a),list(b))}
    return True if (len(comp) == 1 and next(iter(comp)) == True) else False


Another example comparing against Material.diffuse_color using the helper function:

import bpy

def compare_color(a, b, t=0.001):
    from math import isclose
    comp = {isclose(i, j, abs_tol=t) for i, j in zip(list(a),list(b))}
    return True if (len(comp) == 1 and next(iter(comp)) == True) else False

ctx = bpy.context
obj = ctx.object

# Object color as list
obj_clr = obj.active_material.diffuse_color

for o in ctx.scene.objects:
    if o != obj and o.type not in ('LIGHT', 'CAMERA', 'EMPTY'):
        # Compare both lists
        if compare_color(obj_clr, o.active_material.diffuse_color):
            o.select_set(True)


Further Reading: Select an object by name in 2.8 and Set active object in 2.8